Blower

ABSTRACT

A blower ( 1 ) has a blow fan ( 20 ) provided in a casing ( 10 ), a drive device ( 30 ) for rotating the blow fan ( 20 ), and a blow duct ( 40 ) for discharging airflow outside, which the air flow is generated by the rotating blow fan ( 20 ), wherein a dust proof cover ( 60 ) is attached to a suction inlet ( 11 ) formed in the casing ( 10 ), and openings ( 64   a   , 65   a ) for drawing outside air are formed in the left and right side faces ( 64, 65 ) of the dust proof cover ( 60 ), and the left and right side faces ( 64, 65 ) are inclined inward in the right-and-left width direction as they extend downward. According to such a configuration, the openings ( 64   a   , 65   a ) of the dust proof cover ( 60 ) are prevented from being clogged with dust such as dead leaves to prevent overheating of the drive device ( 30 ).

This application is a National Stage Application of PCT/JP2007/067497, filed 7 Sep. 2007, which claims benefit of Serial No. 2006-267304, filed 29 Sep. 2006 in Japan and which application(s) are incorporated herein by reference. To the extent appropriate, a claim priority is made to each of the above disclosed applications.

TECHNICAL FIELD

The present invention relates to a blower for blowing off an object such as dead leaves and sprigs accumulated on the ground and cleaning the ground.

BACKGROUND ART

With respect to a blower for blowing off an object such as dead leaves and sprigs accumulated on the ground and cleaning it, there exists the blower having a blow fan provided in a casing, an engine for rotating the blow fan, and a blow duct for discharging airflow outside, which the air flow is generated by the rotating blow fan.

Such a blower is adapted to be mounted on a shouldering frame and thereby to be able to be carried in a state of being shouldered by a worker; she/he discharges high-speed airflow toward the ground from a nozzle of a blower pipe connected to a blow duct, and thereby, can blow off an object such as dead leaves and sprigs accumulated on the ground and clean it.

Furthermore, in the casing of the blower is formed a suction inlet for drawing outside air into the casing; when the blow fan is rotated, the outside air sucked in the casing from the suction inlet is high-speed airflow by the rotating blow fan. This airflow plays a role of cooling the engine as well as it is discharged from the blow duct.

Moreover, as shown in FIG. 10, to the suction inlet of a conventional blower 100 is attached a dust proof cover 160 for preventing a foreign matter from being sucked. This dust proof cover 160 is configured so that a horizontal upper face 162 and vertical left and right side faces 165 are formed, and to draw outside air from lattice-form openings 162 a, 165 a formed in the faces 162 and 165 (for example, see paragraphs 0013-0014 and FIG. 2 in Japanese Patent Laid-Open Publication No. 2001-241019).

DISCLOSURE OF THE INVENTION

However, with respect to the conventional dust proof cover 160, because the openings 162 a, 165 a are formed in the horizontal upper face 162 and the vertical left and right side faces 165, dust such as dead leaves stuck to the faces 162 and 165 of the cover 160 is sucked to the openings 162 a, 165 a, and is difficult to drop.

Then, when an operation of the blower 100 is continued in a state of the openings 162 a, 165 a being clogged with dust such as dead leaves, there exists a difficulty that an amount of air sucked into a casing 110 is reduced, a cooling efficiency of an engine (not shown) is reduced, and a trouble such as a seizure of an engine occurs due to overheating of the engine.

Consequently, a problem of the present invention is to provide a blower which can solve the difficulty, prevent an opening of a dust proof cover from being clogged with dust such as dead leaves, and prevent the overheating of a drive device.

In order to solve the problem, the present invention relates to a blower comprising: a blow fan provided in a casing; a drive device for rotating the blow fan; and a blow duct for discharging airflow outside, which the air flow is generated by the rotating blow fan, wherein a dust proof cover is attached to a suction inlet formed in the casing, and openings for drawing outside air are formed in the left and right side faces of the dust proof cover, and wherein the left and right side faces are inclined inward in a right-and-left width direction as they extend downward.

According to this configuration, the openings are formed in the left and right side faces of the dust proof cover, and the side faces are inclined inward as they extend downward. That is, because the left and right side faces having the openings obliquely extend downward, dust such as dead leaves is difficult to stick to the side faces.

In addition, because the left and right side faces of the dust proof cover obliquely extend downward, even if dust such as dead leaves sticks to the side faces, the dust is easy to drop by self weight, and therefore, can be easily dropped by a vibration of the blower.

Thus according to the blower of the present invention, dust such dead leaves is difficult to stick to the dust proof cover; even if the dust sticks to the cover, the dust easily drops. Accordingly, it is possible to prevent the openings of the dust proof cover from being clogged with dust such as dead leaves and to maintain an amount of air sucked in the casing; therefore, it is possible to prevent the overheating of the drive device.

In addition, when an upper face of the dust proof cover is configured to be closed, an opening is not formed in the upper face of the cover; therefore, even if dust such as dead leaves is accumulated on the upper face, an amount of air sucked in the casing is not reduced; therefore, it is possible to maintain an amount of air sucked in the casing.

With respect to the blower, it is possible to configure eaves-form protrusion portions on the left and right side faces of the dust proof cover.

According to this configuration, dust such as dead leaves sucked to the openings of the dust proof cover contacts top ends of the eaves-form protrusion portions provided on the left and side faces of the cover, and a contact area between the side faces and the dust is small; therefore, it is possible to make it difficult for the dust to stick to the side faces.

In addition, when the eaves-form protrusion portions are formed so that top sides thereof are obliquely inclined downward, the vibration of the blower can easily drop dust such as dead leaves put on the upper face of the dust proof cover.

The blower is provided with a temperature control mechanism of the drive device; the mechanism can be configured to comprise: a temperature detection means for detecting a temperature of the drive device; and a control unit configured to stop the drive device or reduce a rotation number thereof when the temperature of the drive device detected by the detection means is not less than a predetermined temperature.

Here, if the openings of the dust proof cover are clogged with dust such as dead leaves, an amount of air sucked in the casing is reduced and the cooling efficiency of the drive device is reduced, and therefore, the temperature of the drive device is increased.

According to the configuration, when the temperature of the drive device is not less than a predetermined temperature, the drive device is stopped or a rotation number thereof is reduced by the temperature control mechanism; therefore, a speed of airflow generated by the blow fan is reduced, and a suction force for sucking dust such as dead leaves to the openings is reduced. By the reduction of the suction force to the openings, it is possible to drop dust such as dead leaves from the openings of the dust proof cover and to recover the cooling efficiency of the drive device; therefore, it is possible to prevent the overheating of the drive device.

Furthermore, by stopping the drive device or reducing a rotation number thereof by the temperature control mechanism, because it is possible to make a worker know an abnormal change of the drive device, it is possible to prompt her/him to clean the dust proof cover. That is, the temperature control mechanism plays a role of an alarm for informing a worker of the clogging of the openings of the dust proof cover.

In addition, when it is configured that the drive device is stopped or a rotation number thereof is drastically reduced by the temperature control mechanism, a worker easily gets scent of the abnormal change of the drive device.

The blower is provided with the temperature control mechanism of the drive device; the mechanism can be configured to comprise: a rotation number detection means for detecting a rotation number of the drive device; and a control unit configured to stop the drive device or reduce the rotation number when the rotation number detected by the detection means is not less than a predetermined rotation number.

Here, if the openings of the dust proof cover are clogged with dust such as dead leaves, an amount of air sucked in the casing is reduced and a suction resistance of the blow fan is reduced, and therefore, load of the drive device is reduced and the rotation number thereof is increased.

According to the configuration, when the rotation number of the drive device is not less than a predetermined rotation number, the drive device is stopped or the rotation number thereof is reduced by the temperature control mechanism; therefore, speed of airflow generated by the blow fan is reduced, and a suction force for sucking dust such as dead leaves to the openings is reduced. By the reduction of the suction force to the openings, it is possible to drop dust such as dead leaves from the openings of the dust proof cover and to recover the cooling efficiency of the drive device; therefore, it is possible to prevent the overheating of the drive device.

Furthermore, by stopping the drive device or reducing a rotation number thereof by the temperature control mechanism, because it is possible to make a worker know the abnormal change of the drive device, it is possible to prompt her/him to clean the dust proof cover. That is, the temperature control mechanism plays a role of an alarm for informing a worker of the clogging of the openings of the dust proof cover.

In addition, when it is configured that the drive device is stopped or a rotation number thereof is drastically reduced by the temperature control mechanism, a worker easily gets scent of the abnormal change of the drive device.

According to the blower of the present invention, dust such as dead leaves is difficult to stick to the dust proof cover, and even if the dust sticks to the cover, the dust is easy to drop. Accordingly, it is possible to prevent the openings of the dust proof cover from being clogged with dust such as dead leaves, to maintain an amount of air sucked in the casing, and to maintain the cooling efficiency of the drive device; therefore, it is possible to prevent a trouble such as a seizure of an engine due to the overheating of the drive device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing a blower of a first embodiment and is a perspective view seen from front.

FIG. 2 is a drawing showing the blower of the first embodiment and is a perspective view seen from rear.

FIG. 3 is a drawing showing the blower of the first embodiment and is a perspective view seen from front in a state where a shouldering frame is removed.

FIG. 4 is a drawing showing a dust proof cover in the blower of the first embodiment, and is a perspective view seen from front.

FIG. 5 is a drawing showing the dust proof cover in the blower of the first embodiment, and is a perspective view seen from rear.

FIG. 6 is an outline configuration diagram of a temperature control mechanism in a blower of a second embodiment.

FIG. 7 is a flowchart showing control by the temperature control mechanism in the blower of the second embodiment.

FIG. 8 is an outline configuration diagram of a temperature control mechanism in a blower of a third embodiment.

FIG. 9 is a flowchart showing control by the temperature control mechanism in the blower of the third embodiment.

FIG. 10 is a drawing showing a conventional blower and is a perspective view seen from front.

DESCRIPTION OF THE SYMBOLS

-   -   1 Blower     -   10 Casing     -   11 Suction Inlet     -   20 Blow Fan     -   30 Drive Device     -   33 Engine     -   40 Blow Duct     -   50 Shouldering Frame     -   60 Dust Proof Cover     -   61 Attachment Plate     -   61 a Opening     -   64 Left-side Face     -   64 a Opening     -   64 b Protrusion Portion     -   65 Right-side Face     -   65 a Opening     -   65 b Protrusion Portion     -   71 Temperature Detection Sensor (Temperature Detection Means)     -   72 Control Unit (Second Embodiment)     -   81 Rotation Number Detection Sensor (Rotation Number Detection         Means)     -   82 Control Unit (Third Embodiment)

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Next will be described embodiments of the present invention with reference to drawings as needed.

In addition, in describing each of the embodiments, a same symbol will be given to a same component, and a duplicate description thereof will be omitted.

First Embodiment

Firstly, a first embodiment of the invention will be described. In addition, in descriptions below, a front direction, a rear direction, a left direction, and a right direction correspond to those shown in each drawing.

[Configuration of Blower]

A blower 1 shown in FIGS. 1 and 2 is a power blower for blowing off an object such as dead leaves and sprigs accumulated on the ground and cleaning it, and comprises a blow fan 20 (see FIG. 3) provided in a casing 10, a drive device 30 for rotating the blow fan 20, and a blow duct 40 for discharging airflow outside, which the air flow is generated by the rotating blow fan 20.

The blower 1 is mounted on a shouldering frame 50, and thereby, is able to be carried in a state of being shouldered by a worker; she/he discharges high-speed airflow toward the ground from a nozzle of a blower pipe (not shown) connected to a blow duct 40, and thereby, can blow off an object such as dead leaves and sprigs accumulated on the ground and clean it.

<<Configuration of Casing, Blow Fan, and Blow Duct>>

The casing 10 is an approximately circular box in a front view as shown in FIG. 3, and the blow fan 20 is arranged in a center portion of the box.

With respect to the blow fan 20, a plurality of blades 21 are formed around a rotation shaft (not shown) extending in front-and-rear directions in a center portion of the casing 10. When the blow fan 20 is rotated around the rotation shaft, the fan 20 is configured to generate high-speed airflow from front to rear of the fan 20.

Furthermore, in a front face of the casing 10 is formed a suction inlet 11 for drawing outside air in the casing 10. The suction inlet 11 is a circular shape in the front view and is formed at a position fronting the blow fan 20.

Furthermore, in a left side of the casing 10 is formed a duct-side discharge outlet 12 for discharging the airflow generated by the rotating blow fan 20 outside the casing 10; the cylindrical blow duct 40 is connected to the outlet 12.

Moreover, in a rear face of the casing 10 is formed an engine-side discharge outlet (not shown) leading into an engine cover 31 of a drive device 30 described later.

Then, when the blow fan 20 is rotated, outside air sucked in the casing 10 from the suction inlet 11 is high-speed airflow by the rotating blow fan 20. The airflow is discharged outside from the duct-side discharge outlet 12 through the blow duct 40 as well as in the engine cover 31 from the engine-side discharge outlet, and cools the engine (not shown).

<<Configuration of Drive Device>>

The drive device 30 is arranged, as shown in FIGS. 1 and 2, on a rear side of the casing 10, and the engine (not shown) is accommodated in the box-form engine cover 31 attached to the rear face of the casing 10. An output shaft of this engine is configured to be connected to the rotation shaft of the blow fan 20 (see FIG. 3), and so that the blow fan 20 is rotated by a driving force of the engine.

In addition, below the engine cover 31 is provided a fuel tank 32 for reserving fuel supplied to the engine.

<<Configuration of Shouldering Frame>>

The shouldering frame 50 is configured, as shown in FIGS. 1 and 2, with a horizontal plate-form base plate 51, and a back pad plate 52 vertically provided on a front end edge of the plate 51. In addition, to the back pad plate 52 is attached a belt (not shown) for a worker to shoulder the shouldering frame 50.

With respect to this shouldering frame 50, the casing 10 and a lower portion of the drive device 30 are fixed to an upper face of the base plate 51, and the front face of the casing 10 is fixed to a rear face of the back pad plate 52 through a dust proof cover 60; thereby, the blower 1 is in a state of being mounted.

Then a worker can carry the blower 1 in a state of shouldering it by shouldering the shouldering frame 50 in a state of the front face of the shouldering plate 52 of the frame 50 being contacted with her/his shoulder.

<<Configuration of Dust Proof Cover>>

As shown in FIG. 3, to the suction inlet 11 of the casing 10 is attached the dust proof cover 60 for preventing a foreign matter from being sucked.

With respect to the dust proof cover 60, as shown in FIGS. 4 and 5, an upper face 62, a lower face 63, a left-side face 64, and a right-side face 65 are raised toward front on an outer peripheral edge of a reverse-trapezoidal attachment plate 61 in a front view. In addition, the upper face 62 is closed and configured so that no opening is formed.

The left and right side faces 64, 65 are inclined inward in right-and-left width direction as they extend downward, and lattice-form openings 64 a, 65 a are formed in the faces 64, 65.

Furthermore, with respect to the openings 64 a, 65 a, a plurality of lateral members forming lattices are provided with eaves-form protrusion portions 64 b, 65 b, respectively.

Specifically, the protrusion portions 64 b of the left-side face 64 are protruded in left-and-right directions from both faces of the face 64, and are inclined downward as the portions 64 b extend from a right end side (inner end side) to the left end side (outer end side). In addition, the protrusion portions 65 b of the right-side face 65 are protruded in the left-and-right directions from both faces of the face 65, and are inclined downward as the portions 65 b extend from a right end side (inner end side) to the left end side (outer end side).

In the attachment plate 61 are formed a circular opening 61 a in a front view at a position corresponding to the suction inlet 11 (see FIG. 3) of the casing 10, and a plurality of through holes 61 b for attaching the dust proof cover 60 to the casing 10 (see FIG. 3).

With respect to the dust proof cover 60, a rear face of the attachment plate 61 is attached to the front face of the casing 10 by a bolt (not shown) inserted through each of the through holes 61 b (see FIG. 4), and the rear face of the back pad plate 52 of the shouldering frame 50, as shown in FIG. 1, abuts with front end edges of the upper face 62, the lower face 63, the left-side face 64, and the right-side face 65. Thus a space is formed that is surrounded by the back pad plate 52, the attachment plate 61, the upper face 62, the lower face 63, the left-side face 64, and the right-side face 65.

Furthermore, as shown in FIG. 3, it is configured that the blow fan 20 is fronted from the opening 61 a of the attachment plate 61 in a state of the dust proof cover 60 being attached to the front face of the casing 10.

Then, when the blow fan 20 is rotated, outside air is drawn in the dust proof cover 60 from the openings 64 a, 65 a of the left and right side faces 64, 65 of the dust proof cover 60 (see FIGS. 4 and 5), and the outside air is sucked in the casing 10 through the opening 61 a of the attachment plate 61; thereby, high-speed airflow is generated by the rotating blow fan 20.

[Action and Effect of Blower of First Embodiment]

According to the blower 1 of the first embodiment, the openings 64 a, 65 a are formed in the left and right side faces 64, 65 (see FIGS. 4 and 5) of the dust proof cover 60, and the faces 64, 65 are inclined inward in the left-and-right width direction as they extend downward. That is, because the left and right side faces 64, 65 having the openings 64 a, 65 a obliquely extend downward, dust such as dead leaves is difficult to stick to the faces 64, 65.

Furthermore, because the left and right faces 64, 65 obliquely extend downward, even if dust such as dead leaves sticks to the faces 64, 65, the dust is easy to drop by self weight, and can be easily dropped by a vibration of the blower 1.

Moreover, because the upper face 62 of the dust proof cover 60 is closed and an opening is not formed, even if dust such as dead leaves is accumulated on the face 62, an amount of air sucked in the casing 10 is not reduced.

Furthermore, the left and right faces 64, 65 of the dust proof cover 60 are provided with the eaves-form protrusion portions 64 b, 65 b, and dust such as dead leaves sucked to the openings 64 a, 65 a formed in the faces 64, 65 contact outer ends (top ends) of the portions 64 b, 65 b. Accordingly, because a contact area between the left and right faces 64, 65 of the dust proof cover 60 and dust such as dead leaves is small, it is possible to make it difficult for the dust to stick to the faces 64, 65.

Furthermore, because the eaves-form protrusion portions 64 b, 65 b are formed so that their outer end sides are obliquely inclined downward, dust such as dead leaves put on the upper faces of the portions 64 b, 65 b can be easily dropped by the vibration of the blower 1.

Thus according to the blower 1 of the first embodiment, it is configured that: dust such as dead leaves is difficult to stick to the dust proof cover 60; and even if the dust sticks to the cover 60, it easily drops. Accordingly, because it is possible to prevent the openings 64 a, 65 a of the dust proof cover 60 (see FIGS. 4 and 5) from being clogged with dust such as dead leaves, to maintain an amount of air sucked in the casing 10, and to maintain the cooling efficiency of the engine in the drive device 30, it is possible to prevent a trouble such as a seizure of the engine due to the overheating of the engine.

Modification Example

As above, although the first embodiment of the present invention has been described, the invention is not limited thereto, and can be appropriately modified and changed in design within the spirit and scope of the invention. For example, the left and right faces 64, 65 of the dust proof cover 60 may not be provided with the eaves-form protrusion portions 64 b, 65 b. Moreover, forms of the openings 64 a, 65 a formed in the left and right faces 64, 65 are not limited if a structure thereof is configured to be able to prevent a foreign matter from being sucked in the dust proof cover 60.

Second Embodiment

Next will be described a second embodiment of the present invention. A blower of the second embodiment differs in a point that a temperature control mechanism of a drive device is provided, in addition to the configuration of the blower of the first embodiment.

[Configuration of Temperature Control Mechanism]

The temperature control mechanism of the second embodiment of the invention comprises, as shown in FIG. 6, a temperature detection sensor 71 (“temperature detection means” in Claims) for detecting a temperature of an engine 33 of the drive device 30, and a control unit 72 configured to reduce a rotation number of the engine 33 when a temperature T of the engine 33 detected by the sensor 71 is not less than a predetermined temperature.

<<Configuration of Temperature Detection Sensor>>

The temperature detection sensor 71 is not limited if it can detect the temperature of the engine 33; for example, it is possible to configure the sensor 71, using a thermistor.

Furthermore, although a position of the temperature detection sensor 71 attached to the engine 33 is not limited, it is desirable to attach the engine 33 to a cylinder head whose temperature is easy to rise.

<<Configuration of Control Unit>>

The control unit 72 comprises a storage unit and a CPU (Central Processing Unit) and controls the rotation number of the engine 33, based on the detected temperature T of the engine 33. In addition, the control by the control unit 72 is achieved by the CPU performing a program. Furthermore, in the storage unit is stored a predetermined temperature T1 which is a maximum temperature when the engine 33 is normally driven.

The control unit 72 is configured so that when the temperature T detected by the temperature detection sensor 71 is lower than the predetermined temperature T1, the unit 72 drives the engine 33 by a rotation number N' of a normal time; and when the temperature T detected by the temperature detection sensor 71 is not less than the predetermined temperature T1, the unit 72 drastically reduces the rotation number of the engine 33 to a rotation number N2.

[Control by Temperature Control Mechanism]

Subsequently, control by the temperature control mechanism of the second embodiment will be described with reference to FIGS. 6 and 7 as needed.

When the engine 33 of the drive device 30 is started, the control unit 72 of the temperature control mechanism obtains the temperature T of the engine 33 detected by the temperature detection sensor 71, and determines whether or not the temperature T is not less than the predetermined temperature T1 (step S11).

Here, if the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60 are clogged with dust such as dead leaves, an amount of air sucked in the casing 10 is reduced and the cooling efficiency of the engine 33 of the drive device 30 is reduced; therefore, the temperature T of the engine 33 is increased.

Then, when the temperature T of the engine 33 detected by the temperature detection sensor 71 is not less than the predetermined temperature T1 (Yes in the step S11), the control unit 72 drastically reduces the rotation number of the engine 33 to the rotation number N2 (step S12).

After the control unit 72 drastically reduces the rotation number of the engine 33 in the step S12, the unit 72 again performs the step S11. At this time, when the temperature T of the engine 33 detected by the temperature detection sensor 71 is not less than the predetermined temperature T1, the control unit 72 repeats the step S12; when the temperature T of the engine 33 detected by the temperature detection sensor 71 is lower than the predetermined temperature T1 (No in the step S11), the unit 72 drives the engine 33 by the rotation number N' of the normal time (step S13).

In addition, the control unit 72 is configured to perform the control from the step S11 to the step S13 for every predetermined time.

[Action and Effect of Blower of Second Embodiment]

According to the blower of the second embodiment, when the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60 (see FIG. 3) are clogged with dust such as dead leaves, and the temperature of the engine 33 is not less than the predetermined temperature T1, the rotation number of the engine 33 is reduced by the temperature control mechanism; therefore, the speed of airflow generated by the blow fan 20 (see FIG. 3) is reduced, and a suction force by which the dust is sucked to the openings 64 a, 65 a is reduced. By the reduction of the suction force of the openings 64 a, 65 a, dust such as dead leaves can be dropped from the openings 64 a, 65 a and the cooling efficiency of the engine 33 can be recovered; therefore, it is possible to prevent the overheating of the engine 33.

In addition, by drastically reducing the rotation number of the engine 33, because it is possible to let a worker get scent of an abnormal change of the engine 33; therefore, it is possible to prompt her/him to clean the dust proof cover 60. That is, the temperature control mechanism of the second embodiment plays a role of an alarm for informing a worker of the clogging of the openings 64 a, 65 a of the dust proof cover 60.

Modification Example

As above, although the second embodiment of the present invention has been described, the invention is not limited thereto, and can be appropriately modified and changed in design within the spirit and scope of the invention. For example, according to the temperature control mechanism of the second embodiment, it is configured that the rotation number of the engine 33 is drastically reduced by the temperature control mechanism when the temperature of the engine 33 is not less than the predetermined temperature T1; however, it may also be configured that the engine 33 is stopped by the temperature control mechanism when the temperature of the engine 33 is not less than the predetermined temperature T1.

According to this configuration, the blow fan 20 (see FIG. 3) is also stopped by the engine 33 being stopped, and there exists no suction force of the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60. Accordingly, it is possible to surely drop dust such as dead leaves from the openings 64 a, 65 a. Furthermore, it is possible to surely let a worker know the abnormal change of the engine 33 by its being stopped.

Third Embodiment

Next will be described a third embodiment of the present invention.

A blower of the third embodiment differs in a point that a temperature control mechanism of a drive device is provided, in addition to the configuration of the blower of the first embodiment.

[Configuration of Temperature Control Mechanism]

The temperature control mechanism of the third embodiment of the invention comprises, as shown in FIG. 8, a rotation number detection sensor 81 (“rotation number detection means” in Claims) for detecting the rotation number of the engine 33 of the drive device 30, and a control unit 82 configured to reduce the rotation number of the engine 33 when a rotation number N of the engine 33 detected by the sensor 81 is not less than a predetermined rotation number N1.

<<Configuration of Rotation Number Detection Sensor>>

The rotation number detection sensor 81 detects the rotation number of the engine 33, and a configuration of the sensor 81 is not limited. For example, the rotation number can be detected by calculating the number from an ignition timing of the engine 33, and by detecting a rotation of an output shaft by a pulse sensor.

<<Configuration of Control Unit>>

The control unit 82 comprises a storage unit and a CPU (Central Processing Unit) and controls the rotation number of the engine 33, based on the rotation number N detected by the rotation number detection sensor 81. In addition, the control by the control unit 82 is achieved by the CPU performing a program. Furthermore, in the storage unit is stored the predetermined rotation number N1 of a rotation number at a time when load of the engine 33 is reduced and the rotation number is increased.

The control unit 82 is configured so that when the rotation number N detected by the rotation number detection sensor 81 is lower than the predetermined rotation number N1, the unit 82 drives the engine 33 by the rotation number N′ of a normal time; and when the number N detected by the sensor 81 is not less than the predetermined rotation number N1, the unit 82 drastically reduces the rotation number of the engine 33 to the rotation number N2.

[Control by Temperature Control Mechanism]

Subsequently, control by the temperature control mechanism of the third embodiment will be described with reference to FIGS. 8 and 9 as needed.

According to the temperature control mechanism of the third embodiment, when the engine 33 of the drive device 30 is started, the control unit 82 obtains the rotation number N of the engine 33 detected by the rotation number detection sensor 81, and determines whether or not the number N is not less than the predetermined rotation number N1 (step S21).

Here, if the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60 are clogged with dust such as dead leaves, an amount of air sucked in the casing 10 is reduced and a suction resistance of the blow fan 20 (see FIG. 3) is reduced; therefore, the load of the engine 33 is reduced and the rotation number thereof is increased.

Then, when the rotation number N detected by the rotation number detection sensor 81 is not less than the predetermined rotation number N1 (Yes in the step S21), the unit 82 drastically reduces the rotation number of the engine 33 to the rotation number N2 (step S22).

After the control unit 22 drastically reduces the rotation number of the engine 33 in the step S22, the unit 82 again performs the step S21. At this time, when the rotation number N of the engine 33 detected by the rotation number detection sensor 81 is not less than the predetermined rotation number N1, the control unit 82 repeats the step S22; when the rotation number N of the engine 33 detected by the sensor 81 is lower than the predetermined number N1 (No in the step S21), the unit 82 drives the engine 33 by the rotation number N′ of the normal time (step S23).

In addition, the control unit 82 is configured to perform the control from the step S21 to the step S23 for every predetermined time.

[Action and Effect of Blower of Third Embodiment]

According to the blower of the third embodiment, as shown in FIGS. 8 and 9, when the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60 (see FIG. 3) are clogged with dust such as dead leaves, and the rotation number of the engine 33 is not less than the predetermined rotation number N1, the rotation number of the engine 33 is reduced by the temperature control mechanism; therefore, the speed of airflow generated by the blow fan 20 (see FIG. 3), and a suction force by which the dust is sucked to the openings 64 a, 65 a is reduced. By the reduction of the suction force of the openings 64 a, 65 a, dust such as dead leaves can be dropped from the openings 64 a, 65 a and the cooling efficiency of the engine 33 can be recovered; therefore, it is possible to prevent the overheating of the engine 33.

In addition, by drastically reducing the rotation number of the engine 33, because it is possible to let a worker get scent of the abnormal change of the engine 33; therefore, it is possible to prompt her/him to clean the dust proof cover 60. That is, the temperature control mechanism of the third embodiment plays a role of an alarm for informing a worker of the clogging of the openings 64 a, 65 a of the dust proof cover 60.

Modification Example

As above, although the third embodiment of the present invention has been described, the invention is not limited thereto, and can appropriately be modified and changed in design within the spirit and scope of the invention. For example, according to the temperature control mechanism of the third embodiment, it is configured that the rotation number of the engine 33 is drastically reduced by the temperature control mechanism when the rotation number of the engine 33 is not less than the predetermined rotation number N1; however, it may also be configured that the engine 33 is stopped by the temperature control mechanism when the rotation number of the engine 33 is not less than the predetermined rotation number N1.

According to this configuration, the blow fan 20 (see FIG. 3) is also stopped by the engine 33 being stopped, and there exists no suction force of the openings 64 a, 65 a (see FIGS. 4 and 5) of the dust proof cover 60. Accordingly, it is possible to surely drop dust such as dead leaves from the openings 64 a, 65 a. Furthermore, it is possible to surely let a worker know the abnormal change of the engine 33 by its being stopped. 

1. A blower comprising: a blow fan provided in a casing; a drive device for rotating the blow fan; and a blow duct for discharging airflow outside, the airflow being generated by the rotating blow fan, wherein a dust proof cover is attached to a suction inlet formed in the casing, and openings for drawing outside air are formed in left and right side faces of the dust proof cover, and wherein the left and right side faces of the dust proof cover are inclined inward in a right-and-left width direction as the left and right side faces extend downward.
 2. The blower according to claim 1, wherein the left and right side faces of the dust proof cover are provided with eaves-form protrusion portions.
 3. The blower according to claim 1 further comprising: a temperature control mechanism comprising: a temperature detection means for detecting a temperature of the drive device; and a control unit configured to stop the drive device or to reduce a rotation number thereof when a temperature of the drive device detected by the temperature detection means is not less than a predetermined temperature.
 4. The blower according to claim 1 further comprising: a temperature control mechanism comprising: a rotation number detection means for detecting a rotation number of the drive device; and a control unit configured to stop the drive device or to reduce the rotation number of the drive device when the rotation number of the drive device detected by the rotation number detection means is not less than a predetermined rotation number. 